Bird survey tracks 38,000km for H5 bird flu as coastal 'smouldering' continues

The University of New South Wales study, supported by the Queensland, New South Wales, Victorian and South Australian governments, has been running for 44 years. Researchers fly at low levels over wetlands and rivers, counting waterbirds aloud into a dictaphone, a method Professor Kingsford compared to a race call. The count covers about a third of the continent each year.

Professor Kingsford, who has been on board for almost all of the counts, said over the decades he had seen a 60 to 70 per cent decline in bird populations, which he attributed to the diversion of water in the Murray-Darling Basin that meant wetlands no longer received the floods they used to. He said populations had stabilised in more recent years due to higher rainfall from La Niña weather patterns and some return of environmental flows.

Now the birds face a new threat: H5 bird flu, which reached Australia in June. The survey developed a protocol for reporting any bird deaths observed. Professor Kingsford said the survey was uniquely placed to monitor the threat, describing it as 'probably the largest surveillance program at the moment for bird flu'.

Professor Kingsford noted hundreds of dead pelicans had been seen inland around the Kati Thanda-Lake Eyre region, but said those deaths were likely a normal part of a boom and bust breeding season. 'This year we found that a lot of these rookeries are sort of getting to the end of their boom period and that's when the chicks die,' he said. 'So we've probably got a few hundred pelicans that have died, nothing to indicate anything like bird flu because you don't see any sick birds.'

Scientist Vidya Bhardwaj from the CSIRO's Australian Centre for Disease Preparedness said outbreaks of H5 bird flu so far appeared to be largely confined to Australia's coastline, and even those cases had slowed down. But she said initial dire predictions had not eventuated, and the disease had not gone away. 'It's arrived, it's in our wild bird population so we now have a situation of coastal smouldering avian influenza,' she said.

Dr Bhardwaj noted that avian influenza virus survives for a much shorter period in hot conditions than in cool wet conditions, so less virus would be expected over summer. 'What it will look like when the season changes again or even during summer is really hard to predict,' she said.

Professor Kingsford said numbers of birds in some wetlands had not been as high as he might have expected, possibly due to the amount of water still present inland from major flooding events. Along South Australia's Coorong, a wetland considered internationally important for migratory birds, he noted few migratory species. He said that as inland waters dry out, populations would become more concentrated, creating its own risk. He expected it was only a matter of time before the annual survey started counting the toll. 'All we can go on is what's happened overseas and it's been devastating there. Many rookeries have had huge impacts like 50 per cent loss,' he said.